1. Technical Field
The present invention relates to an air conditioning system suitable for use in an automotive vehicle.
2. Description of the Related Art
A rotary fluid machine 201 as shown in FIG. 1 is disclosed in Japanese Published Unexamined Patent Application No. 4-134198. This rotary fluid machine 201 is 5 a sort of air conditioning systems. In FIG. 1, a blower 203 is driven by a motor 205 directly connected to the blower 203. The high-temperature pressurized air is cooled by a water-cooled air cooler 207 and further on the basis of adiabatic expansion by a radial turbine 209, and then supplied as a cooling air for air conditioning. Further, the rotational force of the radial turbine 209 is fed-back to the blower 203 and the motor 205 for energy recovery.
In the prior art air conditioning system as described above, however, since the highest possible revolution speed of the motor 205 is about 10,000 r.p.m., when the capacity of the air conditioning system is required to be increased, it is necessary to increase the diameter of blower impellers 211 or the number of impeller stages of the blower 203, thus causing a problem in that the size and the weight of the blower 203 inevitably both increase.